1. Field of the Invention
The present invention relates to a diffusing agent composition, a method of forming an impurity diffusion layer, and a solar battery.
2. Description of the Related Art
Conventionally, in the case of, for example, forming an N-type or P-type impurity diffusion layer in a semiconductor substrate in manufacturing a solar battery, the N-type or P-type impurity diffusion layer is formed by patterning a diffusing agent containing an N-type or P-type impurity-diffusing component on the surface of the semiconductor substrate followed by diffusing the N-type or P-type impurity-diffusing component from the patterned diffusing agent. Specifically, a thermally-oxidized film is first formed on the surface of the semiconductor substrate, and a resist having a predetermined pattern is then laminated on the thermally-oxidized film by a photolithography method. Using the resist as a mask, the thermally-oxidized film that is not masked by the resist is etched with acid or alkali, and the resist is then peeled off so as to form a mask of the thermally-oxidized film. A diffusion film is then formed in a mask opening area by applying a diffusing agent containing the N-type or P-type impurity-diffusing component. An N-type or P-type impurity diffusion layer is then formed by diffusing the diffusion film by heating to high temperature.
As stated above, many processes have been conventionally required for forming an impurity diffusion layer in a semiconductor substrate. Contrary to this, for example, Japanese patent Application Publication Nos. 2003-168810, 2003-332606, and 2006-156646 disclose a method of patterning a diffusing agent on the surface of a semiconductor substrate by using an ink-jet method. An ink-jet method does not require complicated processes compared to a conventional photolithography method, etc., because patterning is performed by selectively discharging a diffusing agent onto the forming region of an impurity diffusion layer from an ink-jet nozzle without using a mask, thus allowing for a pattern to be easily formed while reducing an amount of a liquid to be used.